Repeatedly overapproximate the weak closure as long as we make progress

src/heap/incremental-marking.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 12 matching lines @@
       old_generation_space_available_at_start_of_incremental_(0),
       old_generation_space_used_at_start_of_incremental_(0),
       should_hurry_(false),
       marking_speed_(0),
       allocated_(0),
       idle_marking_delay_counter_(0),
       no_marking_scope_depth_(0),
       unscanned_bytes_of_large_object_(0),
       was_activated_(false),
       weak_closure_was_overapproximated_(false),
+      weak_closure_approximation_rounds_(0),
       request_type_(COMPLETE_MARKING) {}
 
 
 void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,
                                          Object* value) {
   if (BaseRecordWrite(obj, slot, value) && slot != NULL) {
     MarkBit obj_bit = Marking::MarkBitFrom(obj);
     if (Marking::IsBlack(obj_bit)) {
       // Object is not going to be rescanned we need to record the slot.
       heap_->mark_compact_collector()->RecordSlot(HeapObject::RawField(obj, 0),
@@ skipping 499 matching lines @@
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Running\n");
   }
 }
 
 
 void IncrementalMarking::MarkObjectGroups() {
   DCHECK(FLAG_overapproximate_weak_closure);
   DCHECK(!weak_closure_was_overapproximated_);
 
-  GCTracer::Scope gc_scope(heap_->tracer(),
-                           GCTracer::Scope::MC_INCREMENTAL_WEAKCLOSURE);
+  int old_marking_deque_top =
+      heap_->mark_compact_collector()->marking_deque()->top();
 
   heap_->mark_compact_collector()->MarkImplicitRefGroups(&MarkObject);
 
   IncrementalMarkingRootMarkingVisitor visitor(this);
   heap_->isolate()->global_handles()->IterateObjectGroups(
       &visitor, &MarkCompactCollector::IsUnmarkedHeapObjectWithHeap);
 
+  int marking_progress =
+      abs(old_marking_deque_top -
+          heap_->mark_compact_collector()->marking_deque()->top());
+
+  ++weak_closure_approximation_rounds_;
+  if ((weak_closure_approximation_rounds_ >=
+       FLAG_max_object_groups_marking_rounds) ||
+      (marking_progress < FLAG_min_progress_during_object_groups_marking)) {
+    weak_closure_was_overapproximated_ = true;
+  }
+
   heap_->isolate()->global_handles()->RemoveImplicitRefGroups();
   heap_->isolate()->global_handles()->RemoveObjectGroups();
-
-  weak_closure_was_overapproximated_ = true;
 }
 
 
 void IncrementalMarking::PrepareForScavenge() {
   if (!IsMarking()) return;
   NewSpacePageIterator it(heap_->new_space()->FromSpaceStart(),
                           heap_->new_space()->FromSpaceEnd());
   while (it.has_next()) {
     Bitmap::Clear(it.next());
   }
@@ skipping 237 matching lines @@
   if (action == GC_VIA_STACK_GUARD) {
     request_type_ = COMPLETE_MARKING;
     heap_->isolate()->stack_guard()->RequestGC();
   }
 }
 
 
 void IncrementalMarking::Epilogue() {
   was_activated_ = false;
   weak_closure_was_overapproximated_ = false;
+  weak_closure_approximation_rounds_ = 0;
 }
 
 
 void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
   if (IsStopped() && ShouldActivate()) {
     // TODO(hpayer): Let's play safe for now, but compaction should be
     // in principle possible.
     Start(PREVENT_COMPACTION);
   } else {
     Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
@@ skipping 186 matching lines @@
 void IncrementalMarking::IncrementIdleMarkingDelayCounter() {
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 }
 }  // namespace v8::internal